package com.dq.utils.gsonutils.adapter;

import com.google.gson.Gson;
import com.google.gson.JsonSyntaxException;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.internal.bind.DateTypeAdapter;
import com.google.gson.internal.bind.util.ISO8601Utils;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;
import org.apache.commons.lang3.StringUtils;

import java.io.IOException;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

/**
 * @author jcf
 * @Description:
 */

public class DateNullAdapter extends TypeAdapter<Date> {

    public static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
        @SuppressWarnings("unchecked") // we use a runtime check to make sure the 'T's equal
        @Override public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
            return typeToken.getRawType() == Date.class ? (TypeAdapter<T>) new DateTypeAdapter() : null;
        }
    };

    private final DateFormat enUsFormat
            = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.US);
    private final DateFormat localFormat
            = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT);
    private final SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    private final DateFormat iso8601Format = buildIso8601Format();
    private static DateFormat buildIso8601Format() {
        DateFormat iso8601Format = new SimpleDateFormat(
                "yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US);
        iso8601Format.setTimeZone(TimeZone.getTimeZone("UTC"));
        return iso8601Format;
    }

    @Override public Date read(JsonReader in) throws IOException {

        if (in.peek() == JsonToken.NULL) {
            in.nextNull();
            return null;
        }
        String jsonStr = in.nextString();
        if(StringUtils.isBlank(jsonStr)) {
            return null;
        }else {
            return deserializeToDate(jsonStr);
        }
    }

    private synchronized Date deserializeToDate(String json) {
        try {
            return new Date(Long.parseLong(json));
        } catch (Exception e) {
            try {
                return this.localFormat.parse(json);
            } catch (ParseException e1) {
                try {
                    return this.enUsFormat.parse(json);
                } catch (ParseException e2) {
                    try {
///                        return this.iso8601Format.parse(json);
                        return ISO8601Utils.parse(json, new ParsePosition(0));
                    } catch (ParseException e3) {
                        try {
                            return this.simpleDateFormat.parse(json);
                        } catch (Exception e4) {
                            throw new JsonSyntaxException(json, e4);
                        }
                    }
                }
            }
        }
    }


    @Override public synchronized void write(JsonWriter out, Date value) throws IOException {
        if (value == null) {
            out.nullValue();
            return;
        }
        String dateFormatAsString = enUsFormat.format(value);
        out.value(dateFormatAsString);
    }


}